Issue 21

Stuck in Transit. What’s Up with Shiyan-9?

China's first successful launch of the LM-7 on 11 March 2021 carried the Shiyan-9 (SY-9) experimental satellite . SY-9 remains in a Geosynchronous Transfer Orbit (GTO) after 2 months. - SY-9 was placed in a GTO where the satellite normally moves into a drift orbit less than 24 hours after launch. - Instead, SY-9 remai…

China’s first successful launch of the LM-7 on 11 March 2021 carried the Shiyan-9 (SY-9) experimental satellite. SY-9 remains in a Geosynchronous Transfer Orbit (GTO) after 2 months.

– SY-9 was placed in a GTO where the satellite normally moves into a drift orbit less than 24 hours after launch.

– Instead, SY-9 remains in a GTO. The Chinese did make a minor orbit adjustment raising the question of whether the satellite suffered a failure once on orbit.

Launch to Geosynchronous orbit from Wenchang usually entails a short coasting period in LEO at 20° inclination. The launch vehicle re-starts as it approaches the equator to produce the transfer orbit with perigee near the original height and apogee around 36,000 km. First apogee occurs above South America and on the equator. One Earth circuit later, the satellite is back at apogee but near 130° – 140° east longitude, well in view of China and close to its final location.

– The Shiyan-9 appeared normal through the second apogee on 12 March, near 134° east, at 1025 UTC. However the anticipated orbit correction did not occur and a continuing flow of orbit data from Space-Track over the next few days showed SY-9 remained in a transfer orbit.

– The Chinese executed a very short thruster firing that raised perigee by just over 200 km.

China may have intended to SY-9 to go into geosynchronous orbit but a problem may have prevented the onboard thruster from firing as intended. Two months after launch the satellite remains in a transfer orbit, indicating that the problem cannot be fixed.

Alternatively, given the 2020 failure of an earlier LM-7A’s second stage, the Chinese may have deemed the fix too risky for the rocket to carry a major payload. Shiyan-9 may have a cluster of instruments to monitor performance during launch hence the ‘technology experiments’ in the launch announcement. The shortened apogee engine burn could have been to prove the satellite reached orbit undamaged.

Issue 21 - Stuck in Transit. What's Up with Shiyan-9?

Source links: SpaceNews · Zarya · 28 Mar FFF